A tube, or pipe joint, is the connection place or piece between two lengths of pipe (i.e., a tube-to-tube joint) or a length of pipe and a component (i.e., a tube-to-component joint). Tube joints are typically formed between a belled (female) pipe end and a spigot (male) pipe end. The belled and spigot pipe ends may have complex interior surfaces, such as bevels and grooves. Typically, an elastomeric gasket or o-ring will fit within a circumferential groove of one of the pipe ends to facilitate the formation of the tube joint with the other of the pipe ends. The gasket forms a tight seal between the inside surface of the belled pipe and the outside surface of the spigot pipe end inserted therein.
Once the spigot pipe end is inserted into the belled pipe end, the tube joint may be further secured by welding, cementing, coupling via a flange, and so forth. A flange is a projecting rim or collar on the pipe, which holds the pipe in place, gives the pipe strength, and facilitates the joining of the pipe to another object, such as another flange on another pipe. Typically, there are one or more bolt holes circled around the outer edge of each flange, with bolts and nuts holding the two flanges together against a gasket that separates them.
FIG. 1 shows a perspective view of a prior art single tube joint 20. Tube joint 20 includes a first pipe 22 having a first flange 24, and a second pipe 26 having a second flange 28. Once the spigot pipe end on, for example, first pipe 22, is inserted into the belled pipe end on, for example, second pipe 26, first and second flanges 24 and 28, respectively, are coupled together using a bolt 30 and nut 32. Thus, tube joint 20 is formed.
Some applications require the use of sets of pipes that run roughly parallel to one another. These applications include, for example, automotive air conditioning plumbing connections from the engine compartment to underbody lines, and from the underbody lines to rear heating, ventilating, and air conditioning (HVAC) unit lines. These automotive air conditioning tubes can be quite long, i.e., in excess of ten feet, can include several bends in the tubing, and/or may include several tube joints coupling sections of the tubing to achieve the final length.
The formation of tube joints using separate flanges, as shown in FIG. 1, at each junction of each of the sets of tubes requires multiple fasteners to attach sections of the pipes, resulting in undesirably high costs and undesirably complex manufacturing and assembly. Accordingly, dual flange systems have been developed for use with sets of pipes that run roughly parallel to one another.
FIG. 2 shows a perspective view of a prior art dual tube joint 34 joining first and second pipes 36 and 38, respectively, to third and fourth pipes 40 and 42, respectively. Tube joint 34 includes a flange 44 having a first passage sized to accommodate third pipe 40 and a second passage sized to accommodate fourth pipe 42. Flange 44 may be retained on each of third and fourth pipes 40 and 42 by brazing, cementing, or by flaring the end of each of third and fourth pipes 40 and 42 to a diameter that is larger than the first and second passages of flange 44.
Tube joint 34 further includes a hooked flange 46 retained on second pipe 38. Once the spigot pipe ends on, for example, first and second pipes 36 and 38, are inserted into the belled pipe ends on, for example, third and fourth pipes 40 and 42, hooked flange 46 is swiveled about second pipe 38 and hooked over first pipe 36. A wedge (not shown) may be forced about the hook portion of hooked flange 46 to secure first pipe 36. A bolt 48 is then directed through each of flange 44 and hooked flange 46 to form dual tube joint 34.
The combined use of flange 44 and hooked flange 46 is less costly and less complex than using separate flanges, as shown in FIG. 1. However, in some applications, a hooked flange may inadequately secure the pipes, depending upon the joint seal design and the pressure of the fluid carried in the pipes. In addition, flange 44 and hooked flange 46 can be bulky and difficult to handle during manufacturing. Moreover, a flange that includes a wedge design requires extra components, which is unwieldy for handling during manufacturing and assembly.
Thus, what is needed is an improved flange for retaining sets of tubes that run roughly parallel to one another.